Taking into account the local weather in Oiapoque is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually October and September with an average temp of 80°F, while the coldest months are July and June with an average of 77°F. The rainiest months in Oiapoque are May, February, April, and January, with each month seeing an average of 15 inches of rainfall.